Dedicated breast radiation imaging/therapy system

ABSTRACT

System, apparatus and methods specialized for breast and related tissue radiation therapy and imaging of a prone patient but also usable for supine patient if desired or needed. A special treatment radiation source such as a LINAC unit generates radiation of types and energy ranges specifically matched to breast tissue. Any one or more of several imaging technologies may be used to localize the tissue to be irradiated and to generate information for therapy planning, adjustment, and verification.

REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part of parent application Ser.No. 11/903,859 filed on Sep. 24, 2007, which in turn is related toInternational application No. PCT/US07/017470 filed Aug. 3, 2007,claiming the benefit of provisional application Ser. No. 60/835,803filed Aug. 3, 2006. This patent specification incorporates by referencethe content of each of said earlier-filed applications, as well as thecontents of the references cited in the text below.

FIELD

This patent specification is in the field of radiation therapy andassociated imaging and therapy planning/adjustment/verification, andspecifically pertains to dedicated, specialized radiation therapy of apatient's breast and associated imaging, planning, and verificationprocedures.

BACKGROUND

Radiation therapy has long been used in medicine. Typically, high energyradiation from sources such as linear accelerators and radioisotopes isused, especially in whole-body, external beam systems where theradiation may need to penetrate a significant amount of tissue in orderto reach the target volume and attain within the target volume theprescribed therapeutic dose level and fractionation scheme. Theirradiation of normal tissue is a necessary physical consequence of allmodes of radiotherapy and typically becomes the limiting factor in anygiven patient's therapy regimen. In procedures that use radiationsources inside the patient's body, a similar challenge is theundesirable but unavoidable exposure of normal tissue. Conventional,whole-body, external beam systems can be used for breast therapy as wellbut their large, whole body geometry tends to lead to undesirableirradiation of significant amounts of healthy tissue. Also, whole body,external beam systems may be designed to irradiate at energy levels thatare not optimized for breast tissue. In order to reduce normal tissueirradiation and achieve sufficient target volume dose, efforts have beenmade to find other approaches for breast radiation therapy, leading tomethods that include, in addition to the orthovoltage radiationtreatment disclosed in said earlier-filed patent applications, proposalsby others such as (1) internal breast brachytherapy which involvesinserting catheters or needles in the breast and placing radioactivesubstances in or through the catheters or needles or using radioactivelycoated needles, (2) surgically implanting a balloon in the breast andselectively delivering radioactive material to the balloon through acatheter, (3) surgically positioning a miniature x-ray tube inside thebreast, (4) external stereotactic brachytherapy that involvescompressing the breast between two sets of conforming channels throughwhich a radioactive substance is placed in close proximity to thebreast, (5) using orthovoltage radiation from an external kilovoltagex-ray source that irradiates the breast from the side or possiblythrough a purposely designed surgical opening in the tissue, (6) using aLINAC radiation source that rotates in a horizontal plane to irradiate adownwardly protruding breast of a patient on a table with an opening forthe breast, and imaging the breast with that source or an adjunctsource, and (7) combining a radioactive substance with a biologicallyactive material designed to uptake selectively in the breast tissuewhere it decays and provides a therapeutic dose (such as monoclonalantibodies) or a substance which causes the tumor to be moreradiosensitive during the treatment.

An external beam radiation therapy treatment typically involves therapyplanning in which the location and perhaps other characteristics of alesion or other target volume or other tissue to be treated or avoidedand monitored are identified by one or more imaging technologies such asultrasound, X-ray computed tomography, static and dynamic planarimaging, nuclear medicine imaging, and magnetic resonance imaging.Information from these imaging modalities is used in computer processingto develop a treatment plan for the directions, energies, and durationsof the therapy radiation beams and the number and frequency of thetreatment sessions. In addition, before each radiation therapy sessionimages of the lesion and/or other target volume or other tissue may betaken to check the position of the target volume and other tissuerelative to the geometry of the radiation therapy system, and variouspositioning aids may be used in the therapy system to verify andmaintain a desired geometric relationship between the radiationtreatment beam(s) and the target tissue and possibly other tissue.Brachytherapy also typically involves similar treatment plan andverification procedures. Typically, the treatment plan and verificationimaging is done on equipment physically separate from the radiationtreatment equipment. Although care can be taken to preserve the positionof the tissue of interest relative to frames of reference that pertainto both the imaging equipment and the treatment equipment, there is arisk that transferring the patient from one piece of equipment toanother may disturb that relationship, with the result that the actualradiation treatment may not match the planned treatment.

See, for example, H. E. Johns & J. R. Cunningham. The Physics ofRadiology, Ch. Thomas, 1983; S. C. Formenti, External-BeamPartial-Breast Irradiation, Seminars in Radiation Oncology, Elsevier2005, 82-99; G. Jozsef, G. Luxton, S. C. Formenti, Application ofradiosurgery principles to a target in the breast, A dosimetric study,Med. Phys. 27 (5). May 2000, 1005-1010; O. Gayou, D. S. Parda, M.Miften, Patient dose and image quality from mega-voltage cone beamcomputed tomography imaging, Med. Phys. 34 (2). February 2007, 499-506.

Despite such advances in radiation therapy systems, including for breastradiation, it is still desirable to improve breast radiation therapy bymaking it more effective and efficient.

SUMMARY OF THE DISCLOSURE

Disclosed is a dedicated system for radiotherapy of the breast andrelated tissue of a patient in the prone position, with radiation beamsthat can rotate below the patient about a vertical axis but in additioncan rotate about an axis angled to the vertical to treat breast-relatedtissue such as axillary lymph nodes without turning the patient over.Maintaining the patient in the same prone, breast-pendulous position canensure good registration between the treatment beams and target volume,and good consistency with treatment plans for both breast and relatedtissue, especially when the patient preferably is maintained in the sameposition and in the same equipment for treatment planning and/orverification imaging as well as for radiation treatment. Further, thesystem can include a mode in which the patient can be treated in thesupine position or in another position, if desired or if called for byspecial circumstances. The system includes imaging functionalities thatshare a spatial frame of reference with the treatment functionalities,whether or not they also share components, and can verify and/or adjusta treatment plan or generate a treatment plan through two-dimensional(2D) and/or three-dimensional (3D) imaging/planning. The distancebetween the radiation source for treatment/imaging and the target volumecan be varied if desired so the radiation source can move about thetarget volume or some other center rather than about a fixed isocenter.This can be done by one or both of source motion and patient tablemotion. The system can further include sensors/transmitters that can beimplanted or otherwise secured in or to the patient, or can be otherwisefixed relative to a system frame of reference, to verify the position ofa target volume or other tissue relative to the radiation beam(s) and/orto measure the radiation dose in two or three dimensions. Thesensors/transmitters preferably include data storage and/or transmissionfunctionalities to provide information to the system, preferably on anessentially real time basis subject to inherent information processingand equipment response time delays. As an alternative or addition tobeing imaged for treatment planning and/or verification in the same setof equipment, the patient can be on a patient table or couch that fitsboth the treatment/imaging system and conventional imaging modalitiessuch as CT scanners so that the patient can remain in or convenientlyand accurately resume the same position, such as the prone position witha breast protruding-downwardly through an opening or into a depressionof the patient table or couch, when imaged for treatment planning at onesystem and then when positioned for treatment/verification at anothersystem. The patient can be positioned on the table and couch in theprone position with the protruding breast immobilized in an effort tomaintain or accurately resume its position relative to the table orcouch, and can be imaged in a CT scanner for radiation planning and thenlater positioned at the disclosed system for treatment in which theposition of the breast or other target tissue relative to the systemframe of reference is known from the information provided from treatmentplanning and the fact that the position of the table or couch relativeto the treatment system also is known, e.g., from mechanical,electromagnetic (e.g., optical or electrical) or other table mountinginterlocks. The imaging functionalities of the disclosed system caninclude 2D and/or 3D imaging systems such as portal imaging using thetreatment radiation source, an x-ray imaging system using componentsmounted in known relationship to the system spatial frame of reference,nuclear medicine imaging (including metabolic activity imaging) usingdetectors also mounted in the same system as the radiation treatmentsource and in a known spatial relationship with the system frame ofreference, ultrasound imaging with transducers maintained in knownpositions in the system frame of reference, and/or other imagingmodalities. Suction or other devices can be used to pull breast tissueaway from the chest wall as needed and/or to stabilize the breast forimaging/treatment. The system can be used for traditional treatmentplans that use fractional doses over a longer period of time such as anumber of weeks or for partial breast irradiation that typically treatsonly a part of the breast (e.g., a lumpectomy site) but over a shorterperiod of time such as once or twice a day for five days. Also disclosedare methods of using the system and methods of imaging, treatmentplanning/verification/adjustment and radiation treatment.

In one non-limiting embodiment the system comprises a table or couch forthe patient to lie prone with at least one breast protruding downwardlythrough an opening or extending into a depression in the table or couch.Preferably a positioning device is used to maintain a reasonablyconsistent and stable position of the breast relative to the patienttable or couch and the imaging and treatment system spatial frame ofreference and, if desired, to help pull tissue away from the chest wall.In an imaging mode, the system provides information for identifying theposition of the breast, the target volume in the breast and/or of someother tissue relative to both the system geometry and pre-treatmentpatient geometry by utilizing imaging technologies such as one or moreof x-ray planar and computed tomography or tomosynthesis, nuclearmedicine, ultrasound, other imaging modalities, and position-indicatingand/or monitoring devices that can be implanted in or otherwise securedto or near the tissue of interest and are specifically designed to workwithin the confines of the system and patient geometry (and preferablycan store and/or transmit information regarding position and dose). Thispre-treatment imaging takes place before at least the first treatmentsession but may be repeated before additional treatment sessions, andcan also be used to identify or estimate other characteristics such asshape and size of a lesion or other target volume parameters related tothe tissue along intended therapy radiation paths and also to identifycritical structure volumes whose unintended irradiation is to beminimized, characteristics of other portions of the breast and perhapsof other anatomy, and the like.

In a treatment planning/adjustment/verification mode, the system usesinformation obtained from other imaging modalities and/or informationfrom the imaging mode of the system disclosed in this patentspecification to plan treatment or at least to verify/adjust treatmentplans and/or verify the position of the lesion or other target volumeand/or of other body parts relative to system and patient geometry.While typically treatment planning and/or verification take place beforeand/or after a treatment session, it is also possible in the disclosedsystem and method to augment such procedures with updating the treatmentplan before a given radiation fraction is delivered to the patient, andeven during delivery, to achieve effective on-the-fly image guidedradiation therapy and/or dynamic adaptive radiation therapy. Thetreatment radiation can be controlled through controlling one or moreof, e.g., the treatment beam intensity, duration, and shape on the fly,using feedback from imaging modalities such as portal imaging,ultrasound or another modality, of source within the response delaysinherent in the imaging, feedback and radiation beam shaping equipment.In a radiation therapy mode of the system disclosed in this patentspecification, a therapy radiation source below the patient table orcouch moves about the downwardly extending breast of a patient in theprone position and emits radiation in energy ranges that are uniquelysuited to breast-related radiation treatment. Importantly, the therapyradiation source can move not only in a horizontal plane (e.g., about avertical axis) but also in other planes (e.g., about a non-verticalaxis) to irradiate breast-related tissue such as the patient's axilla,target volumes that are very close to the chest wall, and other lymphnodes away from the breast. Also importantly, the therapy radiationsource can rotate or otherwise move about the lesion or other targetvolume or about other loci to direct radiation along paths that maintaina low skin dose or otherwise reduce dose outside the target tissue. Thesystem directs and otherwise controls the radiation, preferably inaccordance with current or updated treatment plans.

Preferably, the therapy radiation source is a special linear accelerator(Linac) that has two important characteristics—it emits treatmentradiation that can be uniquely suited to breast-related tissue, and itis sufficiently compact to be mounted below the prone patient table formovement about a patient's breast such as in a horizontal plane and alsofor movement about the breast such as in a plane at an angle to thehorizontal in order to direct primary radiation at other target tissuethat may be associated with the breast. Thus, the source can rotateabout a vertical axis and/or about an axis that extends upwardly but atan angle to the vertical to enable therapy radiation to be directed totarget volumes outside the prone patient's breast if desired, such as ator near the patient's chest wall or the patient's axilla. In addition,if desired the therapy radiation source can be moved above the patientor to other positions suitable for irradiation of a supine patient or apatient in another position. The linear accelerator produces a maximumenergy that can be set at a value, or can vary, in the range of about1-10 MeV Bremstrahlung photons, and preferably about 4-6 MeVBremstrahlung photons. As an alternative example, the treatmentradiation can be charged particles including but not limited toparticles such as electrons, protons, and deuterons. Electrons for atreatment beam can come from the linear accelerator source when theconventional Bremstrahlung target is removed and appropriate beamshaping fields are provided. Other particles for a treatment beam cancome from other accelerating sources known in high-energy physics.

The imaging system preferably uses penetrating radiation from anexternal source but may use, instead or in addition, radiation emittedfrom the breast and/or related tissue, such as from a radiation emittingsubstance injected or otherwise introduced into the patient's body, andcan use ultrasound imaging. In one example, portal imaging is used inwhich a Linac-based source also provides imaging radiation, and animaging detector that is suitable for such high-energy radiationgenerates the image(s). Different energy levels of penetrating radiationfrom the source may be used for imaging versus therapy, if desired.Alternatively, a source different from that used for therapy can be usedto provide imaging radiation. As a non-limiting example, imagingradiation can come from an x-ray source of the type typically used inx-ray mammography or for imaging the chest, and the imaging detector canalso be of the type used in x-ray mammography or chest radiography, andpreferably is a flat panel detector of the type commercially availablefrom the common assignee, Hologic, Inc. If the source of the imagingradiation is internal, suitable imaging detectors are used, such asSPECT, PET, or nuclear medicine imaging detectors. Another imagingmodality that can be used is ultrasound, preferably carried out in amanner that also provides information to positionally relate the imagedtissue with the geometry of the therapy radiation system and thepatient's reference frame established before therapy and updated asneeded during the course of therapy. A CT scanner suitable for breastimaging may be included in the system. Only one of the imagingmodalities identified above may be used, or a combination of two or moreimaging modalities can be used, to provide information for therapyplanning, updating, and verification. Preferably, the imaging systemalso moves, e.g., rotates, under the prone patient's table, about avertical or non-vertical axis, and can be moved to the patient level orabove the patient if desired to image a patient who is in the prone orother position, and preferably but not necessarily the rotation or othermotion centers on the lesion or other target volume. Preferably, theimaging modality produces three-dimensional information, such asinformation based on tomosynthesis, CT scanning, stereotactic imaging,3D ultrasound imaging, or other 3D imaging modalities.

The imaging information is used to generate both traditional, static,forward planned treatment plans as well as inverse planned, dynamicintensity modulated treatment plans using state-of-the-art integratedoptimization methods that can be based on known treatment planningtechnology used for whole-body radiation therapy systems, such as thosecommercially available from Varian Medical Systems of Palo Alto, Calif.,Philips Medical Systems of Andover, Mass., and CMS Inc. of St. Louis,Mo., but taking into account the unique geometry of the breasttherapy/imaging system disclosed in this patent specification and itsother unique parameters such as optimized multileaf collimator leafsizes designed for targeting smaller breast lesions or otherbreast-related target volumes rather than the typically larger targetvolumes addressed by whole body systems, and the photon or particleenergy levels which are also closely matched to breast-related tissue.

The patient's breast can be immobilized and maintained in position forpre-treatment planning in one or more imaging system and for treatmentby devices that include but are not limited to thermoplastics, vacuumfixation bags, foam padding, appendage fixation devices, cones, vacuumand/or adhesives applied to such cones, or other means. Devices of thisnature are proposed, e.g., by MedTec of Orange City, Iowa under thetrade name Horizon Breastboard and by Varian Medical Systems.

BRIEF DESCRIPTION OF THE DRAWINGS

The features of the subject matter of this disclosure can be morereadily understood from the following detailed description withreference to the accompanying drawings wherein:

FIG. 1 illustrates a top view of an embodiment comprising an integrationof a breast therapy system and multiple breast imaging systems.

FIGS. 2 a-2 d illustrate a top view of the therapy system of FIG. 1 inseveral different positions of a therapy radiation source.

FIG. 3 illustrates a top view of a patient table for use in the systemof FIG. 1.

FIG. 4 a illustrates a side view of a patient table and a center ofrotation of the radiation source about an upwardly extending axis.

FIG. 4 b illustrates a side view of a patient table and a center ofrotation of the radiation source about a laterally extending axis.

FIG. 5 a illustrates a perspective view of the imaging/therapy system inrelation to a desired isocenter of rotation.

FIG. 5 b illustrates a side view of the system.

FIG. 6 a is a schematic illustration of an example of a radiationtherapy and imaging system in side view, and FIG. 6 b is a schematicillustration of the system in a front view.

FIG. 7 is is a schematic illustration of a system in side view thatincludes CT imaging provisions.

FIG. 8 illustrates depth dose distribution characteristic of heavycharged particles, with a Bragg peak.

FIG. 9 illustrates range energy relationship for protons.

DETAILED DESCRIPTION

In describing preferred embodiments, specific terminology is employedfor the sake of clarity. However, the disclosure of this patentspecification is not intended to be limited to the specific terminologyso selected and it is to be understood that each specific elementincludes all technical equivalents that operate in a similar manner. Inaddition, a detailed description of known functions and configurationswill be omitted when it may obscure the subject matter of the presentinvention.

As illustrated in FIG. 1, a non-limiting example of the system comprisesa table or couch 101 that is especially adapted to support a patient inthe prone position but may also be used to support a patient in otherpositions such as in the supine position or another position. FIG. 1also illustrates one or more imaging systems discussed below in moredetail for localizing and identifying a lesion or abnormality or targetvolume, a radiation source such as a special Linear Accelerator (LINAC)105 for producing therapy radiation, and a motorized cantilevered stand106. For clarity, the table is illustrated in FIG. 1 with a cutout 109to allow visualizing the components that are below the table. Preferablythe LINAC device 105 is a compact version capable of producingpenetrating radiation uniquely suited to breast-related tissue ratherthan optimized for whole-body radiation therapy. Preferably, the imagingand therapy systems move about the patient's breast, preferably thoughnot necessarily in rotation, and preferably the motion is centered onthe lesion or target volume for therapy irradiation. However, asdiscussed below the system may include provisions for moving the therapyand/or imaging components in a manner suitable for patients in otherpatient positions, such as the supine patient position.

The imaging systems in FIG. 1 example may include: an x-ray system thatuses an x-ray source 102 and x-ray digital imaging detector (flat panel)120, a stereotactic x-ray imaging system where two x-ray sources 102 and103 are used with respective x-ray imaging panels 120 and 113 (or oneset of a source such as 102 and a detector such as 120 is moved to oneposition for one x-ray image and another position for another imagetaken at a different angle relative to the patient's breast), PET orSPECT imaging panels or ultrasound transducers 104, combinations of twoor more of the imaging systems identified above, or other imagingsystems If an x-ray imaging system is used, it can use only one, orboth, of sources 102 and 103 and respective x-ray detector panels 113and 120, to image the patient's breast or other patient tissue. Imagingsource 102 and x-ray panel 120 are mounted to move about the breast as aunit, to image the breast from different angles. If source 103 and panel113 are used, they also rotate or otherwise move as a unit, and if bothsource/panel sets are used, the two sets can rotate as a unit orindividually. In each case, the motion can be about a center 107 thatcan be at the lesion or target volume or about some other center. Thex-ray imaging system(s) may be used to derive projection tomosynthesisimage data, for example by using motion and image reconstruction asdisclosed in commonly assigned U.S. Pat. Nos. 7,245,694, 7,233,005,7,123,684, 7,122,803, 6,851,851, and 6,282,264, or to derivestereotactic information, for example as discussed in U.S. Pat. No.5,803,912 or U.S. Patent Publication 2004/0171933 A1.

FIGS. 2 a-2 d are top views of the system that illustrate examples ofthe range of positions of the therapy system in relation to patienttable 101 (that again is shown with cutout 109 to allow seeingcomponents below the table). A motorized stand 106 supports table 101for up-down motion and, if desirable, for motion along and across thelength of the table, and also can support the imaging and therapysystems for rotation in a circle 111 representing a preferred 360 degreerange of rotation of LINAC 105 and of the imaging system(s) around aselected center 107. If portal imaging is used, a portal imagingdetector 108 and the LINAC device 105 can move as a unit for imaging.

FIG. 2 a illustrates the LINAC device at 0° relative to prone table 101and isocenter 107. Illustrative cutout 109 reveals the LINAC source 105,center 107, and a radiation detector 108. FIG. 2 b illustrates LINACsource 105 at 180° relative to patient table 101 and center 107.Illustrative cutout 109 reveals center 107 and detector 108. FIG. 2 cillustrates LINAC source 105 at approximately 45° relative to table 101and center 108. Illustrative cutout 109 reveals center 107 and detector108. FIG. 2 d illustrates LINAC source 105 at 270° relative to pronetable 101 and center 107. Illustrative cutout 109 reveals center 107 anddetector 108. In a non-limiting example, circle 111 representing thediameter and range of rotation of LINAC source 105 and imaging detector108 preferably has a diameter of approximately three meters. Stand 106preferably extends approximately 1 meter from a wall. An range ofrotation through an angle smaller than 360° can be used as analternative.

FIG. 3 illustrates additional features of patient table 101 as seen intop plan view. Table 101 comprises left and right removable mesh panels303, 304 that cover respective left and right openings in the table.When a mesh panel is removed from the table, the opening allows apatient's breast to extend downwardly for imaging and/or radiationtherapy. The panels are designed to be replaced by a breast stabilizingaide, such as an aide made of an “Aquaplast” material or comparablematerial forming a semi-rigid thermoplastic surface around a breast. Thesystem operating in an imaging mode with some or all of the associatedmodalities can be used to help establish the position and orientation ofthe stabilizing aide and to correlate what will become a semi-rigidsurface of the thermoplastic material to the breast, the target volumesand the system reference frames. Additional or alternative stabilizingaides such as other thermoplastics, vacuum fixation, personalpositioning cups, or variations of positioning boards and coaches may beemployed in the radiotherapy apparatus disclosed herein.

The stabilizing aide(s) or combinations thereof preferably facilitateimmobilizing a breast for imaging so that the target volume can beaccurately and conveniently located in relation to patient and systemgeometry and the lesion or other radiation target volume can then begiven a planned radiotherapy dosage. The use of stabilizing aidesdescribed herein and variations thereof can assist the radiotherapysystem in providing consistent and precise irradiation of a patient'sanatomy on a daily or other basis. The stabilizing aides describedherein are relatively inexpensive and can be re-fabricated as neededduring the course of therapy for clinical (anatomy changes, adema, etc)or patient comfort requirements. As in the case of the stereotacticimaging and biopsy table available from the common assignee under thename MultiCare, the table surface can be shaped, originally or with thehelp of special pillows, to provide patient comfort and to extend theappropriate anatomy as much as possible below the patient table.

Additionally, implantable or otherwise attachable position and/or dosesensors for use within or near a patient's breast or other anatomy canbe utilized to further increase the accuracy and effectiveness of anindividualized patient radiotherapy treatment plan, optionally incombination with one or more breast stabilizing aides. There areimplantable position sensors capable of communicating anatomicalpositioning information, an example of which is available from CALYPSOMedical od Seattle, Wash. One or more implantable position sensors couldbe placed within a patient's breast and surrounding anatomy and usingwireless technology communicate with an embodiment of the radiotherapysystem. The combination of implantable position sensors in communicationwith an embodiment of the radiotherapy system using one or more imagingmodalities can accurately determine patient geometry in relation to theradiotherapy system geometry thereby allowing accurate and dailyirradiation, or irradiation at a different schedule, of a patientconcurrent with an individualized patient radiotherapy treatment plan.

Implantable or otherwise attachable dose monitoring sensors such asthose available from Sicel Technologies, Inc. of Morrisville, N.C. canbe used within an embodiment of the disclosed radiotherapy system inaddition to or optionally independent of implantable position monitors.Implantable monitoring sensors such as those from Sicel Technologies,Inc. can collect and store data related for example to tumor cellkinetics and physiology, pH or oxygen levels, temperature, uptake andretention of chemotherapeutic agents, as well as the radiation dosedelivered to a region of a patient's anatomy. Said monitoring sensorsthen use wireless technology to communicate collected data to receiverslocated outside a patient's body. In a preferred embodiment of theradiotherapy system, one or more implantable monitors can be used in anon-limiting example as radiation dose monitors and can be implanted ina patient at or near the lesion to be treated with therapeutic radiationand optionally surrounding tissue as well. Implanted radiation dosemonitors are able to communicate to the radiotherapy system preciselywhat radiation dose is striking a patient's anatomy. Precise internalradiation dose information from implanted dose monitors can accuratelyprovide dose information to doctors, physicians, and embodiments of theradiotherapy system herein thereby limiting over- or under-irradiationof a patient's anatomy and aiding in accurate and consistent dailytreatment according to a patient's radiotherapy treatment plan. Strayradiation possibly striking other areas of a patient not intended to beirradiated can be monitored by properly implanted or otherwise secureddose monitors thereby increasing patient safety. Both position and dosemonitors described herein are small devices capable of implantationusing commercially available biopsy systems such as from the SurosCorporation, a subsidiary of the assignee of this patent specification,and methods in current clinical use.

FIG. 3 further illustrates degrees of freedom of the motion of patienttable 101. The four directional arrows 302 represent the direction ofmotions along which motorized stand 106 can move prone table 101 (inaddition to any up-down or tilting motion). In a preferred butnon-limiting embodiment, table 101 can move approximately 10 centimetersin any direction from a resting position in the horizontal xy-planeparallel the floor. In a particular implementation, movement overdistances greater or smaller than 10 cm can be selected. X and Ydirections are shown by axis 305. Stand 106 also can be configured tomove the patient table in the vertical position, and/or to tilt table101, if desired. LINAC source 105 is shown in FIG. 3 at a 180° positionrelative to table 101. Arc 306 is placed in FIG. 3 for illustrativepurposes to exemplify a curved direction of motion of LINAC source 105around table 101, preferably about an isocenter of the system (notshown). In a non-limiting example, the rotational movement of LINACsource 105 can be combined with the vertical and horizontal movement ofprone table 101 by motorized stand 106 allowing desired target volumesof a patient's breast and surrounding tissue to be imaged and receiveappropriate doses of therapeutic radiation in accordance with anindividual patient's radiation therapy plan.

FIG. 4 a is a side view of an example of the system, with LINAC source105 at a 180° position around center 107. A radiation beam centerline403 is shown of a shaped beam, e.g. a conical beam or a beam with adifferent cross-section and intensity distribution within thecross-section, exiting LINAC source 105, passing through center 107 andimpinging on imaging detector 108. An additional feature is an optionalbeam blocker 608 that substantially stops primary photon energy thatpasses through imaging detector 108. Table 101, which is not shown toscale in terms of thickness, further comprises rounded openings 401 fora patient's breast, directly above center 107. Z-Y directional axis 402is illustrated to show both the z-direction and y-direction of thesystem relative to the side view illustrated in FIG. 4 a. A motioncontrol 610 supports source 105, imaging detector 108, and beam blocker608 and provides interface electrical and electronic connections betweensource 105, detector 108, and a sub-system 612 that serves as a systemcontrol and for processing and displaying data. Unit 610 and itsconnections to other units are shown schematically but it should beunderstood that the unit typically contains motors and associatedcomponents that impart the desired motions to source 105, imagingdetector 108, and beam blocker 608, including motion in the horizontalplane (flat or curved) about center 107, tilting so that the motionabout center 107 is in a plane (flat or curved) angled to the horizontaland such that at least source 105 can be at the level of or abovepatient table 101, and translating motion that moves center 107 to theleft or to the right or up or down as seen in FIG. 4 a. The schematicconnections shown between unit 610 and source 105 and imaging detector108 represent both mechanical and electrical/electronic two-waycommunication. The two-directional arrows in t he connections to units105, 108, and 608 schematically illustrate telescoping mechanism thatcan be motor-driven, e.g., by fluidic or electrical motors, up and downalong the lengths of the mechanical supports. Unit 612 need not be undertable 101; in fact, typically it is not in the same room as thetherapy/imaging system. For clarity, the imaging systems illustrated inFIG. 1 are not shown in FIG. 4 a but it should be understood that theycan be mounted to and electrically/electronically connected to unit 610in a manner in which their positions are known relative to the systemframe of reference. Alternatively, they can be mounted and otherwiseconnected to a separate motion control and interface configured to movethem in a way that does not interfere with the therapy radiation andportal imaging components. One of the motions of source 105 underpatient table 105 about the patient's breast typically is in ahorizontal plane; however, provisions can be and preferable are made fordeviations from a motion in a flat plane, such as for motion in whichthe vertical elevation of source 105 varies during its motion about thebreast. In addition, as discussed in greater detail in connection withFIG. 4 b below, source 105 can move to positions at the level of, orabove, patient table 101.

FIG. 4 b is similar to FIG. 4 a but illustrates an additional capabilityof a preferred embodiment of the disclosed radiotherapy system. Forclarity, units 610 and 612 and the mechanical and electrical/electronicconnections of FIG. 4 a are not shown in FIG. 4 b but it should beunderstood that they are a part of the system as it would be seen inthis configuration as well. During radiotherapy treatment of a breast orrelated anatomy, it is occasionally desirable to irradiate lymphaticsystems and anatomical tissue located outside of the breast tissuehanging pendulant through an opening or into a depression in table 101.In these cases, an example being when breast cancer metastasizes, it isdesirable to image and irradiate the lymphatic systems associated with abreast including axillary, parasternal, and pectoral nodes located in ornear a patient's armpit area, collarbone area, or axillae. In thesecircumstances, the disclosed imaging and therapy system can optionallytilt radiation source 105 such that a centerline of a therapy radiationit emits is at an angle to the horizontal, e.g. at 45°-55°. Asillustrated in FIG. 4 b (where the angle is greater for clarity ofillustration), an emitted radiation beam centerline 403 can pass upwardsthrough a patient's armpit area and therapeutically irradiate lymphatictissue and surrounding anatomical structures as desired. For thispurpose, source 105 is mounted for movement about center 107 about anon-vertical axis, in a non-horizontal plane that can be flat or curved,and one or both of source 105 and detector 108 can be mounted formovement toward and away from center 107, along radiation centerline403, and thus toward or away from a target volume Radiation detector 108can be moved into a position above patient table 101, to remainperpendicular to the radiation beam centerline 403. In this case it isnot necessary for the radiation beam centerline 403 to pass through anisocenter of the system. The precise pathway of the therapeuticradiation emitted from LINAC device 105 is determined by the treatmentplan for a particular patient. Although not shown in FIG. 4 b, optionalphoton blocker 608 also can be moved from below prone table 101 andpositioned behind radiation detector 108 to absorb primary radiationstill passing through detector 108.

FIG. 5 a illustrates a top view of a portion of the radiotherapy systemcomprising an abstract depiction of a preferred center 107, a LINACdevice 105, additionally a solid state flat panel detector 607, and anoptional beam blocker 608. In the view of FIG. 5 a the patient tablenormally located above the radiotherapy system as well as othercomponents that are visible in other Figs. have been removed from thevisual field so as to more easily illustrate features of a preferredembodiment of the radiotherapy system.

The radiotherapy system of FIG. 5 a comprises a radiation beamcenterline 601, a compact LINAC 602, a target assembly and carousel 603,a primary dual independent collimator 604, a tertiary multi leafcollimator 605, a monitor chamber for beam streams 606, a solid statepanel detector 607 and optionally a beam blocker 608. Also shown in FIG.5 a is center 107 of the system, arrows 609 representing the directionof rotation of the LINAC in tandem with detector 607 and beam blocker608, and x-y system 501 indicating the x-direction and y-direction ofthe machine in this illustration.

FIG. 5 b illustrates a side view of a preferred embodiment of a portionof the radiotherapy and imaging device used in the system shown in FIG.5 a. Again, for ease of illustration some components of the system thatare visible in other Figs. have been omitted. As seen in FIG. 5 b, thepreferred embodiment comprises a linear accelerator (LINAC) 602, atarget assembly and carousel 603, a primary collimator 604, a tertiarycollimator 605, a flat panel detector 607, and an optional beam blocker608.

The radiation source 602 (which can but need not be a Linac source) inthis embodiment preferably operates to produce one or more of thefollowing four therapeutic forms of radiation: (i) direct electron (e−)beams, (ii) direct proton (p+) beams, (iii) high energy Bremstrahlungphotons from an accelerator source, and (iv) high energy photons from aradioisotope (Cobalt-60). When high energy photons from a Bremstrahlungsource are chosen as the therapeutic form of radiation then source 602preferably operates to produce a stream of therapeutic photons having amaximum Bremstrahlung energy at or in the range 1 MeV to 10 MeV,preferably an average energy in the 4 MeV-6 MeV range, or in the 1 MeV-4MeV range. In the most preferred configuration, a compact LINAC in theradiotherapy system produces a stream of therapeutic photons forirradiating breast tissue having an average energy in a specified rangesuitable for breast-related irradiation such as within the range of 1-2MeV. As understood by applicants, a compact LINAC capable of producingtherapeutic photons from a Bremstrahlung source wherein said photonshave an average energy between 1-2 MeV, uses electrons with a peakenergy preferably in the range of 1-6 MeV and more preferably within theenergy range 4-6 MeV. Historically, as understood by applicants, LINACmanufacturers would have attempted to reproduce the effective energy ofCobalt 60 decay photons (1.25 MeV) when making LINAC sources fortreating breast tissue. Cobalt-60 itself could also be used in theradiotherapy device claimed herein and the need for an acceleratorremoved. When a direct electron beam is selected as the therapeutic formof radiation, the LINAC preferably produces a stream of electrons,wherein the electrons have an energy range from 1-10 MeV, preferably inthe range of 4-6 MeV

When a direct beam of protons or other heavy charged particles (i.e.,heavier than electrons) is used as the therapeutic form of radiationfrom a source such as 602, the energy range preferably is selectedaccording to criteria such as discussed in “The Physics of RadiationTherapy”, 3rd Edition, by Faiz Khan. Lippincott, Williams and Wilkins,ISBN 0-7817-3065-1, at pp. 56 & 57 (the “Book”). As seen in FIG. 8,which is a reproduction of FIG. 4.16 in the Book, for such heavyparticles the characteristic distribution of radiation dose with depthin the irradiated tissue is different from that for photons andelectrons. As the beam of heavy particles traverses tissue, thedeposited dose is approximately constant with depth, or rises a little,until near the end of the depth range, where the dose peaks out to ahigh value followed by a rapid fall-off. The energy of other heavycharged particles, such as deuterons, stripped carbon atoms, and others,can be expressed in MeV/u, where u is the mass number of the nucleus, sothat particles that have about the same MeV/u would be expected to haveabout the same range in water or tissue. According to the Book, forwater the rapid rise starts at about 12 cm penetration depth, and peaksat about 15-16 cm and then rapidly falls off. As seen in FIG. 9, whichis a reproduction of FIG. 4.17 in the Book, for 10-20 cm of water (towhich breast tissue is similar in this respect), the proton energy rangeis approximately 80-180 MeV. Preferably, the average energy of the heavycharged particles from a source such as 602 exceeds 20 MeV, morepreferably it exceeds 50 MeV, and most preferably it is in the range80-180 MeV, in each case with a characteristic distribution with depthin breast tissue that has a Bragg peak followed by a rapid fall-off.

When a beam of heavy charges particles is used, an appropriate energycan be chosen to deposit the peak dose at the target volume of tissue.This can be particularly advantageous in the case of target volume thatis at or close to the chest wall, because the rapid fall-off in doseafter the peak leaves organs such as the lungs and heart withessentially zero dose. Another approach is to select heavy chargedparticles energy is to use energy corresponding to the average depth inthe middle of the largest expected uncompressed breast.

Any of the forms of LINACs that are available from manufacturers such asVarian may also be made more compact and thus the machine size smallerby the utilization of superconductive wave guide materials andassociated technologies such as currently being used to generatesuperconducting cyclotrons for treating other deep-seated lesions suchas prostate cancer.

The radiation source 602 produces a radiation beam centerline thatideally passes from the exit of the source straight through a center ofthe systems which is usually the lesion of the breast being treated oris some line through another volume that should be subjected toradiation therapy.

The target assembly and carousel 603 included in the radiotherapyapparatus is used in an embodiment of the radiotherapy apparatus toswitch the type of therapeutic radiation chosen for a particular volumein a patient's breast or surrounding tissue. In an electron mode, theradiotherapy apparatus can emit beta rays that are produced in a LINACor comparable radiation source. While in a photon mode, the radiotherapyapparatus can be configured for the production of photons such as gammaor x-rays.

Following the target assembly and carousel is the primary dualindependent collimator 604. The primary collimator 604 is followed bythe tertiary or multi leaf collimator 605 that can produce in anon-limiting example a 3 mm leaf width at radiation and rotationalcenter 107 of the system for precision treatment of voxels locatedwithin the breast.

The radiotherapy apparatus additionally can house a monitor chamber 606positioned before the multi leaf collimator to assist in determining theamount of radiation being emitted from the radiation source andsubsequently delivered to a particular volume in a patient. Preferably,monitor chamber 606 would remain in dynamic communication with aconcurrent radiation monitoring system so that the radiotherapy systemas accurately as possible provides therapeutic radiation in accordancewith an individualized radiotherapy patient treatment plan.

After passing through the center 107, the radiation strikes a solidstate flat panel detector 607 used for portal imaging. The flat paneldetector 607 is moveable relative to the beam of radiation so that itcan be placed in the path of the beam for imaging and taken out of thepath of the beam for radiation treatment.

Optionally, a beam blocker 608 can be placed in the path of the beam toeffectively stop radiation that has passed through the irradiatedvolume. As shown in FIGS. 5 a and 5 b, optional beam blocker 608 isplaced within the path of the radiation emitted from source 602illustrated by photon beam centerline 601 and positioned downstream ofcenter 107 and flat panel detector 607. The optional beam blocker 608can cut down the cost of shielding the room thereby reducing thestructural footprint of a room housing this system, and making thesystem as a whole easier and less expensive to install and operate inhospitals, clinics, and other such facilities.

FIGS. 6 a and 6 b illustrate a variation of the system in which patienttable 101 is supported on a motorized pedestal 650 that can selectivelymove table 101 along some or all the x, y, and z axes illustrated inFIGS. 6 a and 6 b, and also can tilt table 101 about some or all ofthese the axes. Another motorized pedestal 652 supports a motorizedplate 654 that in turn supports an arm 656 to which is mounted anotherarm 660 supporting therapy radiation source 105, portal imaging detector108, and blocking plate 608 and any imaging system schematicallyillustrated at 658. Pedestal 652 selectively rotates plate 654 to movearm 656 and the components it carries between the positions shown insolid and in dotted lines, including any intermediate position.Motorized plate 654 selectively moves arm 656 and the componentsattached to it up and down as illustrated by arrows in the z-directionand also telescopes or otherwise extends arm 656 and the components itcarries in the y-direction as also illustrated by a bidirectional arrow.Arm 656 also can be motorized to selectively rotate arm 660 about thez-axis at point 662 as illustrated by a bidirectional curved arrow. Inaddition, arm 660 can be motorized to selectively rotate radiationsource 105 about the x-axis at 664 as illustrated by anotherbidirectional curved arrow. These translational and rotations motionsare powered and controlled by units such as 610 and 612 (FIG. 4 a) thatare omitted from the illustration in FIGS. 6 a and 6 b for clarity. FIG.6 b illustrates the same arrangement as FIG. 6 a but in a frontelevation. Typically the patient would be prone on table 101, with abreast extending downwardly through an opening or into a depression intable 101, so that the breast and/or related tissue can be imaged and/ortreated with radiation from below table 101, through the motionsreferred to above patient tissue can also be treated with a radiationbeam that extends from below table 101 through the patient at an angleto the horizontal, for example as illustrated in FIG. 4 b, or at anyother suitable angle to the horizontal. Alternatively, if desired thepatient can be in another position, such as the supine position, to beimaged and/or treated with radiation from a source position above table101, such as illustrated in dotted lines in FIGS. 6 a and 6 b.

FIG. 7 illustrates in side elevation an alternative that includes, inaddition to the arrangement of FIGS. 6 a and 6 b, an arm 700 that is atthe other side of patient table 101 and is mounted to plate 654 in amanner similar to that used for arm 656. Again, plate 654 can bemotorized to selectively move arm 700 up and down as seen in FIG. 7 andillustrated by arrows, and to extend or contract arm 700 in they-direction as illustrated with a bidirectional arrow. Arm 700 carries aspecialized breast CT scanner 712 that is otherwise similar tocommercially available CT scanners available from companies such asGiotto of Italy and distributed in this country primarily for imagingextremities by Hologic, Inc. of Bedford, Mass. but is smaller andlighter to serve as a dedicated breast CT scanner. Other breast-specificCT scanners are proposed by Dr. John Boone (see Synthesis, a publicationof UC Davis Cancer Center, Vol. 8, No. 2, Fall/Winter 2006) and byKoning Corporation of West Henrietta, N.Y., and can be adapted formounting in the system disclosed in this patent specification. Whenplate 654 rotates about the y-axis such that arm 700 is below patienttable 101, a patient breast extending downwardly from the upper surfaceof table 101 can be positioned in an opening 714 of CT scanner 712 andconventional CT scanning can be carried out to generate or adjust orverify treatment plans for treatment that can be carried out with theequipment mounted to arm 656. The components and motions in FIG. 7 thatare in addition to those associated with arm 700, including ones notlabeled or otherwise marked in FIG. 7, can be the same as in FIGS. 6 aand 6 b.

The imaging functionalities of the disclosed system and method can beused to assist in brachytherapy; for example to verify the placement ofradiation sources in the breast relative to breast anatomy, and tomonitor the treatment. Some of the challenges of brachytherapy are toensure that the distance along different directions between theradiation source inside the breast and the surrounding tissue conformsto the treatment plan, and that the tissue to be treated is the plannedtissue. Before the radiation source is introduced or turned on, imagesmay be taken with a modality such as a CT scanner to confirm that thesource is positioned well and to account to anatomy issues such asseromas, scar tissue, and hematomas. If a whole-body CT scanner is used,as is common, the imaging radiation traverses not only the breast thatis being treated but also the other breast and the thorax. After atreatment session, more verification images may be taken. Using theimaging and treatment planning facilities of the system and methoddescribed here would involve imaging radiation dose delivered only tothe breast being treated, and also would facilitate obtaining goodimages in the prone position, with the patient's breast extending down.

Various types of brachytherapy instruments can be used, such as thoseoffered by the assignee of this patent specification under the nameMammosite, by North American Scientific of Chatsworth, Calif., by CiannaMedical of California (formerly Biolucent), by SenoRx of Aliso Viejo,Calif., and other companies. Verification of brachytherapy treatmentparameters using the imaging equipment described in this patentspecification can be done before, during and/or after brachytherapytreatment and can involve placing the patient one or more times in theprone position on a patient table surface such as 101 in FIG. 7, withthe patient's breast pendulously extending downwardly in an opening ordepression in the table surface, and imaging the breast using any one ormore of the modalities discussed in connection with FIG. 7, to obtain 2Dand/or 3D images of the breast and use the the resulting image data forone or more of the following processes: (1) assessing suitability of thebreast for brachitherapy; (2) brachytherapy planning, including whatbrachytherapy device to use, in what way, what radiation agent to useand in what way, the treatment plan in terms of fractional and totaldose, and other parameters related to brachytherapy treatment of thebreast; (3) verifying and if needed adjusting the placement ofbrachytherapy devices in the breast or changing brachytherapy devicesand/or internal radiation sources as desired, for example to ensure goodcontact between the device and breast tissue in the surgical cavity andto consider and account for anatomical features such as seromas andother anatomical irregularities; (4) assessing effects of brachytherapytreatment such as changes in breast tissue at or near the surgicalcavity, and possibly modifying the treatment plan as a result of suchassessment; and (5) post brachytherapy assessments. One significantbenefit of using for this purpose the system described in this patentspecification is that only an affected breast is being imaged so that ifpenetrating radiation is used, no primary beam will be directed to othertissue. Another is that because the disclosed system can use a varietyof imaging modalities, the health professional can select one or moremodalities best suited for the patient. Still another benefit is thatbrachytherapy of a breast can be combined with treatment radiation ofthe same breast or of related tissue in the same system, from anexternal source of radiation, while the patient is in the same positionon the same patient table surface used for imaging, such as the systemof FIG. 7.

All patents and other publications and patent application identifiedabove are hereby incorporated by reference in this patent specification.

While specific example of various features of the disclosed inventionsare discussed above, it should be clear that they are not intended to bethe only examples of the inventions described in the claims below, andshould not be construed as limitations on the scope of the claimedinventions, which scope includes many additional and alternativeexamples and variation that would be appreciated by persons skilled inthe art as being equivalent or as being otherwise within the scope ofthe claimed inventions.

1. A method of treating breast-related tissue of a prone patientcomprising: placing the patient on a surface of a patient table in aprone position, with a patient's breast protruding downward from thetable surface through an opening or into a depression in the table;irradiating the breast-related tissue with treatment radiation from asource mounted for movement about an upwardly extending axis to emit atreatment radiation beam that originates below the table surface; andselectively angling the beam to irradiate with primary radiationportions of the prone patient's breast-related tissue that are above thetable surface.
 2. A method as in claim 1 including imaging the patientplaced on the table, before said irradiating step, with an imagingapparatus keyed to a spatial frame of reference to which said sourcealso is keyed, to develop, adjust or verify a radiation treatment plan.3. A method as in claim 2 in which said imaging comprisesthree-dimensional (3D) imaging.
 4. A method as in claim 3 in which said3D imaging comprises one or more of ultrasound, x-ray imaging, andimaging using radiation emitted from within the patient.
 5. A method asin claim 1 including introducing into the patient one or more sensorsfor at least one of position and radiation dose and utilizing saidsensors in at least one of developing, adjusting, and verifying aradiation treatment plan for the patient.
 6. A method as in claim 1including interacting with a prone patient's breast for imaging andradiation treatment with a device that both tends to pull the breastfrom the patient's chest wall and to secure the breast in a selectedposition.
 7. A method as in claim 1 including imaging the patient'sbreast with CT scanning while the patient is in the position on thepatient table in which said irradiating is carried out.
 8. A method asin claim 1 including detecting treatment radiation delivered to a targetvolume in or at breast-related tissue of the patient and deliveringinformation regarding said detecting to one or more utilizing stationsassociated with the treatment system.
 9. A method as in claim 1including moving the source of the radiation to selectively irradiatepatient tissue from a number of selected directions and selectivelyvarying the distance between the source of the radiation and targettissue.
 10. A system for radiation treatment of breast-related tissuecomprising: a patient table having an upper surface for supporting apatient, said table having a selectively revealed opening or depressionfor a patient breast to extend downwardly from the patient table surfacewhen the patient is in the prone position on said table; a therapyradiation source selectively emitting therapy radiation and a mountingstructure supporting the source and selectively moving the source in afirst motion in which it irradiates a first target volume with a primaryradiation beam that has a centerline below the table surface and in asecond motion in which it irradiates a second target volume with a withprimary radiation beam that has a centerline angled from the horizontaland intersecting the table surface.
 11. A system as in claim 10 in whichthe first target volume is at a downwardly protruding breast of apatient in the prone position on the patient table and the second targetvolume is at the patient's axilla.
 12. A system as in claim 10 furtherthe mounting structure includes structure supporting the source formotion in which the source emits a therapy beam from a location abovethe table surface to directly irradiate breast-related tissue of apatient in the supine position on said table surface.
 13. A system as inclaim 10 including a table support and a an interlock mechanismconfigured to releasably secure the table at a selected positionrelative to a system frame of reference in which the source is at aknown position, said interlock mechanism also configured to mate with aseparate imaging device operative to generate imaging information for aradiation treatment plan for the patent, said treatment plan beingspatially referenced to an interlocked position of the table to theimaging device.
 14. A system as in claim 10 including a CT scannermounted in the system and selectively brought in position for CT imagingof a patient in the prone position on said patient table.
 15. A systemas in claim 10 including an imaging system mounted in a known frame ofreference relative to the therapy radiation source for selectivelyimaging breast-related tissue.
 16. A system as in claim 15 in which saidimaging system selectively provides 2D images of said tissue.
 17. Asystem as in claim 15 in which said imaging system selectively provides3D imaging information of said tissue.
 18. A system as in claim 10 inwhich said mounting structure includes a positioning mechanismselectively varying a distance between said source of therapy radiationand said target volume.
 19. A system as in claim 10 including a controlunit directing the radiation source in accordance with previouslygenerated treatment plans.
 20. A system as in claim 10 in which saidmounting structure comprises a rotating plate support on which saidtherapy radiation source is mounted for rotation about an axis extendingalong a length of said patient table.
 21. A system for radiationtreatment of breast-related tissue comprising: a patient table having anupper surface for supporting a patient, said table having a selectivelyrevealed opening or depression for a patient breast to extend downwardlyfrom the patient table surface when the patient is in the prone positionon said table; a therapy radiation source selectively emitting therapyradiation and a mounting structure supporting the source and selectivelymoving the source in a first motion in which it irradiates a firsttarget volume with a primary radiation beam that has a centerline belowthe table surface and in a second motion in which it irradiates a secondtarget volume with a with primary radiation beam that has a centerlineangled from the horizontal and intersecting the table surface; andwherein said therapy radiation comprises heavy charged particles havingaverage energy in excess of 20 MeV and having a characteristic dosedistribution with depth in breast tissue that has a Bragg peak followedby a rapid fall-off.
 22. A system as in claim 21 wherein said averageenergy exceeds 80 MeV.
 23. A system as in claim 22 wherein said averageenergy is in the range of approximately 80-180 MeV.
 24. A method oftreating breast-related tissue of a prone patient comprising: placingthe patient on a surface of a patient table in a prone position, with apatient's breast protruding downward from the table surface through anopening or into a depression in the table; irradiating thebreast-related tissue with treatment radiation from a source mounted formovement about an upwardly extending axis to emit a treatment radiationbeam that originates below the table surface; and selectively anglingthe beam to irradiate with primary radiation portions of the pronepatient's breast-related tissue that are above the table surface; saidtreatment radiation comprising heavy charged particles having averageenergy in excess of 20 MeV and having a characteristic dose distributionwith depth in breast tissue that has a Bragg peak followed by a rapidfall-off.
 25. A method as in claim 24 wherein said average energyexceeds 80 MeV.
 26. A method as in claim 22 wherein said average energyis in the range of approximately 80-180 MeV.
 27. A method of verifyingbrachytherapy treatment comprising: placing a patient in a proneposition on a patient table surface having an opening or depression inwhich a patient's breast involved in brachitherapy treatment pendulouslyextends downwardly; imaging the breast with radiation to verifybrachytherapy related parameters using an imaging device located belowthe patient table surface; and generating image data for the patent'sbreast for assessing brachytherpay-related parameters.
 28. A method asin claim 27 including delivering therapy radiation from an externalsource to the patient's breast and/or related anatomy while the patientis in said prone position.
 29. A method as in claim 27 in which saidimage data includes data for verifying the position of brachytherapydevices relative to anatomy in the patient's breast.
 30. A method as inclaim 27 in which said image data includes data for verifying effects ofbrachytherapy on anatomy in the patent's breast.